Transcript
TTR™20 Handheld TTR
TTR™20 Handheld TTR
DESCRIPTION The Megger TTR20 is an automatic hand-held battery operated transformer turns ratio test set. It is used to measure the turns ratio, excitation current and polarity of windings in single- and three-phase distribution and power transformers (tested phase by phase), potential & current transformers, and tapped transformers. The unique design of the TTR20 allows the user to operate the test set while holding it in one hand. It effectively eliminates the user from having to kneel or bend down to operate the instrument and speeds up testing time. Realizing the extreme environments in which the TTR20 must operate, special attention has been paid to making it extra rugged, with a high impact, shock resistant case, yet incredibly lightweight at a mere 870 g (1.9 lbs). Its design makes this instrument well suited for use in a variety of harsh environments. The TTR20 is particularly suited for testing in substations, transformer-manufacturing environments, and meter shops. It features a high-contrast, backlit LCD screen which can be seen in bright or ambient light. This unit measures a high turns ratio of 10,000:1 accurately with the lowest excitation voltage. The excellent repeatability of the TTR20 helps the users to determine the condition of transformers under test. It is designed for simple, one button operation with the measured results displayed directly on the easy to read LCD or printed to the optional printer. The TTR20 needs no additional software and comes ready to use complete out of the box. APPLICATIONS The proper operation of a transformer relies almost entirely on the electrical properties of its windings. To
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Single- and three-phase transformer testing
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Fully automatic; fast; easy-to-use; robust; lightweight
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Battery powered
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Tests turns ratio, excitation current, and polarity
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Simple, one-button operation
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Quick-start guide on front panel
ensure continued proper operation, transformers are tested to verify that their electrical properties have not changed from design specifications. A TTR is an extremely useful instrument for testing transformer windings because it can help locate several types of problems within single- and three-phase transformers. It it used to determine the no-load accuracy of CTs and PTs and also determine the need to further test faulty CTs and PTs. The TTR20 applies voltage to the high-voltage winding of a transformer and accurately measures the resulting voltage from the low voltage winding. The ratio of voltages is directly proportional to turns ratio. In addition, the unit measures excitation current and polarity. Transformer Turns Ratio A Transformer Turns Ratio Test Set such as the TTR20 can directly measure the turns ratio of single-phase transformers as well as three-phase transformers. Deviations in these measurements will quickly indicate problems in transformer windings and in the magnetic core circuits. Transformer ratio can change due to several factors, including physical damage from faults, deteriorated insulation, contamination and shipping damage. If a transformer ratio deviates more than 0.5 percent from the rated voltage ratio, it may not operate reliably. To measure small ratio changes such as this, the accuracy of a Megger TTR20 is needed. Transformer Polarity Polarity of a distribution transformer becomes of interest in order to determine its proper connection within a power network. The Megger TTR20 will identify normal (in phase) and reverse polarity of the single-phase transformers.
TTR™20 Handheld TTR FEATURES AND BENEFITS I Fast, easy hand-held operation. No need to kneel or bend down to operate the instrument.
Display full graphics LCD module, adjustable back-lighting, wide temperature range, 128 x 64 dots (21 characters by 8 lines)
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Transformer Winding Phase Relationship ANSI C57.12.70-1978
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Powered by six standard “AA” alkaline batteries; no charger needed. Provides up to 12 hours of field operation. Measures turns ratio range of 10,000:1, with a high accuracy (±0.1%, 0.8 to 2000) at a low excitation voltage. Records ratio errors for bushing CTs to an accuracy of ±0.1% nameplate. This reduces the need for additional test equipment and improves set-up time. Perfect for meter shops, the TTR20 can be used for inspection purposes to determine the no-load accuracy of most CTs and PTs. It also can be used to determine the need to test potentially faulty CTs and PTs. Automatic self-calibration for each test.
SPECIFICATIONS Type of Power Six standard “AA” (IEC LR-6) alkaline batteries Battery Life 12 hours of field operation Excitation Voltage 8 V rms for testing distribution or power transformers and PTs; 0.5, 1.5, or 8 V ac rms for testing CTs. The excitation voltage is switched automatically if excitation current exceeds a preset value.
Safety/EMC/Vibration Meets the requirements of IEC-1010-1, CE and ASTM D999.75 Temperature Range Operating: -20º C to 55º C (-5º F to 130º F) Storage: -50º C to 60º C (-55º F to 140º F) Relative humidity Operating: 0 to 90% noncondensing Storage: 0 to 95% noncondensing Protective Devices High voltage side shorting relay, transient voltage suppressors and gas surge voltage protectors Measuring Time Less than 5 seconds Measurement Method ANSI/IEEE C57.12.90 Dimensions 240 H x 115 W x 50 D mm (9.5 H x 4.5 W x 1.9 D in.) Weight Approximately 1.3 kg (2.8 lb), including leads
Test Frequency 55 Hz internally generated providing a universal 50/60 Hz test set Excitation Current Range 0 to 100 mA, 4-digit resolution
ORDERING INFORMATION
Turns Ratio Range 0.8 to 10,000, 5 digit resolution
Item (Qty)
Cat. No.
Transformer Polarity Normal or reversed
Hand-held TTR20
Current (rms) accuracy (2% of reading + 1 digit)
Combined test leads, "X/H" winding, 1.8 m (6 ft)
TTR20
Included Accessories Instruction manual
Turns Ratio Accuracy 0.1% (0.8 to 2000) 0.15% (2001 to 4000) 0.25% (4001 to 10,000)
Optional Accessories Combined test leads, "X/H" winding, 3.6 m (12 ft)
35942
Combined test leads, “X/H” winding, 6 m (20 ft)
36013
Combined test leads, “X/H” winding, 10 m (33 ft)
36042
Printer package including battery/line power serial thermal printer with paper, battery pack and charger, printer interface cable, 120V, 60Hz Semi-hard fabric transport case
UK Archcliffe Road, Dover CT17 9EN England T (0) 1 304 502101 F (0) 1 304 207342
35938
AVTMTTR20
UNITED STATES 4271 Bronze Way Dallas, TX 75237-1019 USA T 1 800 723 2861 T 1 214 333 3201 F 1 214 331 7399
OTHER TECHNICAL SALES OFFICES Norristown USA, Toronto CANADA, Mumbai INDIA, Trappes FRANCE, Sydney AUSTRALIA, Madrid SPAIN and The Kingdom of BAHRAIN.
35755-1 35788
ISO STATEMENT Registered to ISO 9001:2000 Reg no. Q 09250 Registered to ISO 14001 Reg no. EMS 61597
TTR20_DS_en_V01 www.megger.com Megger is a registered trademark
